System and methods for bone transport

ABSTRACT

A system for bone transport is provided, the system comprising: an adjustable length implant configured for intramedullary placement and comprising a first end configured to be coupled to bone and a second end configured to be coupled to bone, wherein the first end and the second end are displaceable relative to each other along a longitudinal axis; and a driving element configured to be non-invasively activated to displace the first and second ends relative to one another along the longitudinal axis; and a support member having distal and proximal ends, wherein the support member includes a longitudinally extending slot disposed between the distal and proximal ends of the support member, the slot having opposing ends, wherein the slot is configured to pass an elongate anchor such that the elongate anchor is slidable between the first end and the second end of the slot.

CROSS REFERENCE TO RELATED APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 CFR 1.57.

BACKGROUND

Distraction osteogenesis is a technique which has been used to grow newbone in patients with a variety of defects. For example, limblengthening is a technique in which the length of a bone (for example afemur or tibia) may be increased. After creating a corticotomy, orosteotomy, in the bone, which is a cut through the bone, the tworesulting sections of bone may be moved apart at a particular rate, suchas one (1.0) mm per day. New bone may regenerate between the twosections of the bone as they are moved apart. This technique of limblengthening can be used in cases in which one limb is longer than theother, such as in a patient whose prior bone break did not healcorrectly, or in a patient whose growth plate was diseased or damagedprior to maturity. In some patients, stature lengthening is desired andmay be achieved by lengthening both femurs and/or both tibiae toincrease the patient's height.

Bone transport is a similar procedure, in that it makes use ofosteogenesis. But, instead of increasing the distance between the endsof a bone, bone transport fills in missing bone in between. There areseveral reasons why significant amounts of bone may be missing. Forexample, a prior non-union of bone, such as that from a fracture, mayhave become infected necessitating removal of the infected section.Also, segmental defects may be present, the defects often occurring fromsevere trauma when large portions of bone are severely damaged. Othertypes of bone infections or osteosarcoma may require removal of a largepiece of bone (causing a portion of the natural bone to be missing).

Historically, limb lengthening was often performed using externalfixation. The external fixation process involves an external distractionframe which may be attached to two (or more) separate sections of boneby transdermal pins (i.e., passing through the skin). Pin-based methodssuffer from several shortcomings. For example, the pins can be sites forinfection and are often painful for the patient, as the pin placementsite remains a somewhat open wound “pin tract” throughout the treatmentprocess. External fixation frames are also bulky, and can make itdifficult for the patient to comfortably sit, sleep, and move.Intramedullary lengthening devices also exist, such as those describedin U.S. patent application Ser. No. 12/875,585, which is incorporated byreference herein.

Bone transport is frequently performed by either external fixation, orby bone grafting. In external fixation bone transport, a bone segment iscut from the remaining sections of bone and moved by the externalfixation, usually at a rate close to one (1.0) mm per day, until theresulting regenerate bone fills the defect. The wounds created from thepin tracts in external fixation-based bone transport procedures arefrequently even worse than those created by external fixation limblengthening procedures. The pins begin to open the wounds larger as thepins are moved with respect to the skin. In bone grafting, autograft(from the patient) or allograft (from another person) is typically usedto create a lattice for new bone growth. Bone grafting can be morecomplicated and/or expensive than the placement of external fixationpins.

SUMMARY

The present disclosure provides for a method for transporting a portionof bone within a patient having an incomplete bone including providingan adjustable-length implant configured for intramedullary placement andhaving a first end configured to be coupled to bone and a second endconfigured to be coupled to bone, wherein the first end and the secondend are displaceable relative to each other along a longitudinal axis,placing the adjustable-length implant at least partially within themedullary canal of a bone of a subject, the bone having first and secondends and having at least first and second portions having a space therebetween, the first portion of the bone including the first end of thebone and the second portion of the bone including the second end of thebone, creating a third portion of the bone by detaching at least some ofeither the first portion of the bone or the second portion of the bone,wherein the third portion of the bone does not include the first end ofthe bone or the second end of the bone, coupling a support member havingfirst and second ends to the bone by coupling the first end of thesupport member to an external surface of the first portion of the boneand coupling the second end of the support member to an external surfaceof the second portion of the bone, coupling the first end of theadjustable-length implant to one of the first and second portions of thebone, coupling the second end of the adjustable-length implant to thethird portion of the bone, wherein the adjustable-length implantincludes a driving element configured to be non-invasively activatedsuch that a distance between the first end and the second end of theadjustable-length implant is controllably changed such that the thirdportion of the bone is moved along the longitudinal axis in relation tothe first and second portions of the bone, while the first portion ofthe bone and second portion of the bone are not moved in relation toeach other.

The present disclosure additionally provides for a system for bonetransport including an adjustable length implant configured forintramedullary placement and having a first end configured to be coupledto bone and a second end configured to be coupled to bone, wherein thefirst end and the second end are displaceable relative to each otheralong a longitudinal axis, and a driving element configured to benon-invasively activated such that a distance between the first end andthe second end of the adjustable-length implant can be controllablyalong the longitudinal axis, and a support member having first andsecond ends, wherein the support member includes a longitudinallyextending slot disposed between the first and second ends of the supportmember, the slot having a first end and a second end, wherein the slotis configured to pass an elongate anchor such that the elongate anchoris slidable between the first end and the second end of the slot.

The present disclosure further provides for a method for transporting aportion of bone within a patient having an incomplete bone includingproviding an adjustable-length implant configured for intramedullaryplacement and having a first end configured to be coupled to bone and asecond end configured to be coupled to bone, wherein the first end andthe second end are displaceable relative to each other along alongitudinal axis, placing the adjustable-length implant at leastpartially within the medullary canal of a bone of a subject, the bonehaving first and second ends and having at least first and secondportions having a space there between, the first portion of the boneincluding the first end of the bone and the second portion of the boneincluding the second end of the bone, creating a third portion of thebone by detaching at least some of either the first portion of the boneor the second portion of the bone, wherein the third portion of the bonedoes not include the first end of the bone or the second end of thebone, coupling an external fixator to the bone, the external fixatorhaving an external base, a first pin and a second pin, by coupling thefirst pin of the external fixator to the first portion of the bone andcoupling the second pin of the external fixator to the second portion ofthe bone, coupling the second end of the adjustable-length implant tothe third portion of the bone, wherein the adjustable-length implantincludes a driving element configured to be non-invasively activatedsuch that a distance between the first end and the second end of theadjustable-length implant is controllably changed such that the thirdportion of the bone is moved along the longitudinal axis in relation tothe first and second portions of the bone, while the first portion ofthe bone and second portion of the bone are not moved in relation toeach other.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-2 illustrate various views of an intramedullary deviceconfigured for bone transport.

FIG. 3 illustrates a sectional view of the intramedullary device of FIG.2 taken along line 3-3.

FIG. 4A illustrates detailed view 4 of FIG. 3.

FIG. 4B illustrates a sectional view of another embodiment of anintramedullary device.

FIG. 4C illustrates a ring gear insert of the device shown in FIG. 4B.

FIG. 4D illustrates a coupling assembly of the device shown in FIG. 4B.

FIG. 5 illustrates an exploded view of the intramedullary device shownin FIGS. 1-4A.

FIG. 6 illustrates detailed view 6 of FIG. 5.

FIG. 7 illustrates a sectional view of another embodiment of anintramedullary device.

FIG. 8 illustrates a maintenance member of the intramedullary device ofFIG. 7.

FIGS. 9-12 schematically illustrate various driving elements of anintramedullary device.

FIG. 13 illustrates a bone with a portion missing.

FIG. 14 illustrates a system for bone transport coupled to a bone.

FIG. 15 illustrates the system of FIG. 14 after the transport of aportion of bone.

FIG. 16 illustrates a system for bone transport coupled to a bone in aretrograde manner.

FIG. 17 illustrates the system of FIG. 16 after the transport of aportion of bone.

FIG. 18 illustrates an external adjustment device.

FIG. 19 illustrates an exploded view of a magnetic hand piece of theexternal adjustment device of FIG. 18.

FIG. 20 illustrates another embodiment of a system for bone transport.

FIG. 21 illustrates the system of FIG. 20 coupled to a bone.

FIG. 22 illustrates the system of FIG. 21 after the transport of aportion of bone.

FIG. 23 illustrates a kit for an adjustable-length implant.

FIG. 24 illustrates an adjustable-length implant constructed from thekit of FIG. 23.

DETAILED DESCRIPTION

Various adjustable devices for implanting into the body that are capableof changing or working/acting on a portion of the skeletal system of apatient are disclosed herein. In some embodiments, the adjustableimplants are configured for transporting a segment of bone to replacelost portions of bone. Methods for using the adjustable implants fortransporting a segment of bone in order to replace lost portions of boneare also provided. In some embodiments, the method may incorporate oneor more plates. Adjustable devices may include distraction or retractiondevices, for example, distraction or retraction devices configured fororthopedic applications, including, but not limited to scoliosis, limblengthening, bone transport, spinous process distraction, lumbarlordosis adjustment, tibial wedge osteotomy adjustment, andspondylolisthesis. Adjustable devices configured for bone transport mayinclude intramedullary limb lengthening devices.

FIGS. 1 and 2 illustrate an intramedullary device 300 (e.g., anintramedullary lengthening device) comprising a distraction rod 302 anda housing 304. The housing 304 extends between a first end 310 and asecond end 312, as may be better appreciated in the sectional view ofFIG. 3. The housing 304 may be formed as a unitary structure with noseams or joints. Alternatively, the housing 304 may be formed in piecesthat are fused together at seams or joints. As shown in FIG. 3, thedistraction rod 302 has a first end 318 and a second end 320, and isconfigured to be telescopically extendable and retractable relative tothe housing 304 (e.g., within the housing 304). Like the housing 304,the distraction rod 302 may be a unitary structure with no seams orjoints connecting various sub-components. Alternatively, the distractionrod 302 may be formed in pieces that are fused together at seams orjoints. Both the distraction rod 302 and the housing 304 may be madefrom any of a number of biocompatible materials, including titanium, forexample Titanium-6AL-4V, cobalt chromium alloys, and stainless steel.Because the distraction rod 302 and the housing 304 are the primary loadbearing members of the intramedullary device 300, and because neitherhas any external circumferential weld(s), the intramedullary device 300can be capable of withstanding improved loading challenges in comparisonto conventional intramedullary limb lengthening devices. The housing 304contains at least one transverse hole (e.g., two transverse holes 301)for passing bone screws, with which to attach the intramedullary device300 to the bone. The distraction rod 302 contains at least onetransverse hole (e.g., three transverse holes 303), also for the passingof bone screws. As will be readily understood, the number andorientation of the transverse holes 301, 303 may be varied as necessary,useful, or desired for any given application. At the second end 312 ofthe housing 304, a coupling feature 323, provides an interface toreleasably engage with an insertion instrument, such as a drill guide.The drill guide may include a male thread and the coupling feature 323may have a complementary or mating female thread. The intramedullarydevice 300 comprises a magnet 338 which is bonded within a magnethousing 340 and configured for rotation between a radial bearing 344 anda thrust bearing 342 (shown more clearly in FIG. 4A). Between the thrustbearing 342 and the magnet housing 340 is at least one planetary gearstage (e.g., three planetary gear stages 305, 307, 309, as seen in FIG.4A). Each planetary gear stage (e.g., planetary gear stages 305, 307,309) comprises a sun gear (e.g., sun gear 311A, 311B, 311C) and aplurality of planetary gears (e.g., three planetary 313), which arerotatably held within a frame 315 by pins 317. The sun gear 311 iseither a part of the magnet housing 340, as in the case of the sun gear311A of planetary gear stage 305, or a part of the frame 315, as in sungear 311B of gear stage 307 and sun gear 311C of gear stage 309. Therotation of the sun gear 311 causes the planetary gears 313 to rotateand track along inner teeth 321 of a ring gear insert 319. Each gearstage has a gear reduction ratio (e.g., of 4:1), which results in atotal gear reduction (e.g., a total gear reduction of 64:1—provided bythree planetary gear stages each having a reduction ratio of 4:1). Itshould be understood that other gear reductions, and numbers of stagesmay be used.

The frame 315 of the final gear stage (e.g., gear stage 309) passesthrough the thrust bearing 342 and is attached to a lead screw coupler366 such that rotation of the frame 315 of the final gear stage 309causes one-to-one rotation of the lead screw coupler 366. The lead screwcoupler 366 and a lead screw 358 each contain transverse holes throughwhich a locking pin 368 is placed, thus rotationally coupling the leadscrew 358 to the final gear stage (e.g., gear stage 309). A locking pinretainer 350 is slid over and secured (e.g., tack welded) to the leadscrew coupler 366 to radially maintain/retain the locking pin 368 inplace. The distraction rod 302 has an internally threaded end 363, intowhich external threads 365 of a nut 360 are threaded and bonded, forexample with epoxy. The nut 360 has internal threads 367 which areconfigured to threadably engage with external threads 325 of the leadscrew 358, thereby allowing rotation of the lead screw 358 in a firstdirection to distract or extend the distraction rod 302 in relation tothe housing 304. Rotation of the lead screw 358 in a second (opposite)direction retracts or withdraws the distraction rod 302 in relation tothe housing 304. Rotation of the magnet 338 and the magnet housing 340causes rotation of the lead screw. Depending on the gearing included,rotation of the magnet 338 and the magnet housing 340 can cause rotationof the lead screw 358 at 1/64 the rotational speed, but withsignificantly increased torque (64 times, minus frictional losses), andthus an amplified distraction or extension force. O-rings 362 are placedin ring grooves 388 on the exterior of the distraction rod 302 to createa dynamic seal between the housing 304 and the distraction rod 302 thatprotects the internal contents from body fluids. A split washer stop364, located between the distraction rod 302 and the lead screw coupler366, guards against jamming that could otherwise be caused as thedistraction rod 302 approaches the lead screw coupler 366, for exampleif intramedullary device 300 is fully retracted with a high torque(e.g., a high torque applied by an external moving magnetic field).

A maintenance member 346, comprising a curved plate made from amagnetically permeable material (e.g., 400 series stainless steel), issecured to/bonded within the inner wall of the housing 304 (e.g., usingepoxy, adhesive, resistance welding, or other suitable process(es)). Themaintenance member 346 attracts a pole of the magnet 338, thus keepingthe limb lengthening device 300 from being accidentally adjusted bymovements of the patient. However, a strong moving magnetic field, suchas that applied by magnetic adjustment devices known in the art, iscapable of overcoming the attraction of the magnet 338 to themaintenance member 346, rotate the magnet 338, and thereby adjust thelength of the intramedullary device 300. The maintenance member 346 canhave has a thickness of approximately 0.015 inches and can span acircumferential arc of less than about 180° (e.g., an exemplary arc is99°). Of course, other dimensions for the maintenance member 346 arecontemplated, as long as it provides sufficient attractive force(s) tothe magnet 338 to appropriately hold it in place when not beingactuated.

The distraction rod 302 and the housing 304 may be individuallymanufactured, for example by machining processes incorporating manual orautomated lathes. Included within this manufacturing operation may bethe forming of an axially-extending cavity within the housing 304.Post-processing may be included in this operation, for example beadblasting, passivation, and/or anodizing. The distraction rod 302 and thehousing 304 are then prepared for mating. In this operation, the nut 360is bonded into the distraction rod 302 and the O-rings 362 are placedinto the ring grooves 388 as described. The maintenance member 346 isbonded to the housing 304. Then, the magnet 338 is placed into thecavity 390 of the housing 304. In this operation the magnet 338 and themagnet housing 340 are bonded together, and then assembled with theradial bearing 344 into the housing 304 (see FIG. 3). Prior toassembling the radial bearing 344 into the housing 304, the longitudinaldepth of the cavity 390 of the housing 304 is measured, and, ifnecessary, one or more shims may be placed before the radial bearing344. Ideally, the axial play in the assembled components is not so lowas to cause binding, yet not so high as to risk disassembly. Next, thelead screw 358 is prepared for coupling to the magnet 338 that is in thecavity 390 of the housing 304. In this operation the ring gear insert319 is slid into the cavity 390 of the housing 304 until it abuts ledge392. First and second planetary gear stages 305, 307 are then placedinto the assembly as seen in FIG. 4A. The locking pin retainer 350 ispreloaded over the lead screw coupler 366 prior to welding the leadscrew coupler 366 to the final planetary gear stage 309, and is thenslid in place over the locking pin 368 after the locking pin 368 isplaced. Final planetary gear stage 309 is inserted through the thrustbearing 342 and is welded to the lead screw coupler 366, allowing forsome axial play of the thrust bearing 342. The split washer stop 364 isthen placed onto the lead screw 358. The lead screw 358 is then attachedto the lead screw coupler 366 with the locking pin 368, and then thelocking pin retainer 350 is slid over a portion of the ends of thelocking pin 368 and tack welded to the lead screw coupler 366. Thrustbearing retainers 354, 356 are two matching pieces which form acylindrical clamshell around the thrust bearing 342 and the lead screwcoupler 366. The internal diameter of the housing 304 is tinned withsolder, as are the outer half diameter surfaces of each of the thrustbearing retainers 354, 356. Next, the thrust bearing retainers 354, 356are clamped over an assembly comprising the thrust bearing 342, leadscrew coupler 366, planetary gear stage 309, and lead screw 358, and thethrust bearing retainers 354, 356 are pushed together into place withinthe housing 304, for example with the aid of a tool pressed againstchamfers 352 of the thrust bearing retainers 354, 356. The sun gear 311Cof the final planetary gear stage 309 engages with the planet gears 317of the final planetary gear stage 309 and then chamfered edges 394 ofthe thrust bearing retainers 354, 356 are pushed against a chamfer 348of the ring gear insert 319 and a compressive force is held. Next, thethrust bearing 342 and the magnet 338 are axially retained. In thisoperation, the thrust bearing retainers 354, 356 are soldered to thehousing 304 at the tinned portions, thus maintaining compressive force.This may be accomplished using induction heating. The friction of theledge 392 and the chamfered edge 394 against opposing ends of the ringgear insert 319, as well as the wedging between the chamfered edge 394and the chamfer 348, create a resistance to rotation, thus holding thering gear insert 319 rotationally static in relation to the housing 304.Alternatively, the ring gear insert 319 may have a keyed feature thatfits into a corresponding keyed feature in the housing 304, in order tostop the ring gear insert 319 from turning relative to the housing 304(this may be useful if/when the friction on the ends of the ring gearinsert 319 is not sufficient to hold the ring gear insert 319 static).

The distraction rod 302 can then be engaged with the lead screw 358. Inthis operation, an assembly tool, such as a high speed rotating magnet,is used to make the magnet 338 and, consequently, the lead screw 358rotate and the distraction rod 302 is inserted into the housing 304while the lead screw 358 engages and displaces with respect to the nut360 of the distraction rod 302. After the distraction rod 302 isinserted into the housing 304 as described and retracted at leastsomewhat, the distraction rod 302 is still free to rotate with respectto the housing 304. For the stability of the bone pieces beingdistracted, it may be desirable to inhibit rotation between thedistraction rod 302 and the housing 304. One possible method andstructure of doing so is described in relation to FIGS. 5 and 6. Thedistraction rod 302 may be rotationally locked with respect to thehousing 304 by placing an anti-rotation ring 370 over the distractionrod 302 by engaging protrusions 374, one on each side, into grooves 372extending along the distraction rod 302 and then by sliding theanti-rotation ring 370 up to a tapered inner edge 376 of the housing304. The anti-rotation ring 370 and the distraction rod 302 may then berotated until guide fins 382 can be inserted (e.g., slide) into guidecuts 380 in the end of the housing 304. The anti-rotation ring 370 canbe axially snapped into the housing 304 so that flat edge 384 of theanti-rotation ring 370 is trapped by undercut 378. The undercut 378 hasa minimum diameter which is less than the outer diameter of the flatedge 384 of the anti-rotation ring 370, and is temporarily forced openduring the snapping process. As assembled, the anti-rotation ring 370,the housing 304 and the distraction rod 302 are all held substantiallyrotationally static in relation to each other. In addition, when theintramedullary device 300 reaches its maximum distraction length, theends 386 of grooves 372 abut the protrusions 374, thereby keeping thedistraction rod 302 from falling out of the housing 304.

An alternative embodiment of the intramedullary device 300 of FIGS. 1-4Ais shown in a sectional view in FIG. 4B. Much of this embodiment can besimilar or identical to the embodiments shown in FIGS. 1-4A. However,this embodiment varies at least in that it need not have thrust bearingretainers 354, 356. Instead, it may incorporate a thrust bearing ferrulehaving an external tapered end 347. A thrust bearing retainer 337, alocking pin retainer 341, and the thrust bearing ferrule 335 are placedover the thrust bearing 342 and a lead screw coupler 339 and the finalplanetary gear stage 309 are inserted through the thrust bearing 342 andwelded to the lead screw coupler 339. As shown in FIG. 4D, the lockingpin retainer 341 has a relief 361 to allow the passage of the lockingpin 368. After the locking pin 368 is placed, the locking pin retainer341 may be rotated so that the relief 361 is no longer directly over thelocking pin 368 and the locking pin retainer 341 is tack welded orsecured by other methods to the lead screw coupler 339, thus retainingthe locking pin 368. These assembled components are then inserted intothe cavity 390 of the housing 304, where the final planetary gear stage309 is coupled to the other planetary gear stages 305, 307 and themagnet 338. In this embodiment, a ring gear insert 333 (FIG. 4C) has anindentation 351 (e.g., a notch) on each side. A tab 349 on each side ofthe thrust bearing ferrule 335 inserts into each indentation 351 andinhibits rotation of the ring gear insert 333 in relation to the housing304 once the thrust bearing ferrule 335 is engaged into the housing 304.Also in this embodiment, the housing 304 contains internal threading343. The engagement of the thrust bearing ferrule 335 is achieved bytightening external threading 345 of the thrust bearing retainer 337into the internal threading 343 of the housing 304. A tool (not shown)may be engaged into cut outs 357 on either or both sides of the thrustbearing retainer 337 and is used to screw the thrust bearing retainer337 into the internal threading 343 of the housing 304. As shown in FIG.4B, this wedges an internal taper 353 of the thrust bearing retainer 337against the external tapered end 347 of the thrust bearing ferrule 335,allowing the thrust bearing ferrule 335 to apply a controlled load onthe ring gear insert 333, locking the ring gear insert 333 axially androtationally with respect to the housing 304. The thrust bearingretainer 337 contains an axial split on the opposite side (not shown).The split in the thrust bearing retainer 337, allows the outer diameterof the thrust bearing retainer 337 to be slightly reduced (bycompression) while it is inserted into the housing 304, prior to beingthreaded, so that the internal portion of the housing 304 is notscratched during insertion. A ledge 355 is visible on the lead screwcoupler 339 in FIG. 4D. As noted earlier, the split washer stop 364butts up against this ledge 355 to prohibit jamming when the distractionrod 302 is retracted completely.

An alternative embodiment of the intramedullary device 300 of FIGS. 1-4Ais shown in a sectional view in FIG. 7. A maintenance member 397replaces the curved plate maintenance member 346. The maintenance member397 is spaced axially in relation to the magnet 338 within the housing304 of the limb lengthening device 300, but because of its proximity tothe magnet 338, maintenance member 397 is still capable of attracting apole of the magnet 338, thus keeping the limb lengthening device 300from being accidentally adjusted by movements of the patient. Themaintenance member 397 comprises a body 395 and a securement portion391. The securement portion 391 is illustrated as comprising four tabs393, each having an outer radius that is greater than the radius ofcavity 379 in the housing 304. The interference between the tabs 393 andthe cavity 379 is sufficient to hold the maintenance member 379 inplace, so that it cannot turn or move axially in relation to the housing304. Alternatively, the securement portion 391 may be adhesively bonded,welded, or secured by another means to the cavity 379. The maintenancemember 397 includes a ledge 381 which is configured to seat the radialbearing 344. Similar to the embodiments of FIGS. 1-4D, a nose 377 of themagnet housing 340 is pressed into the inner hole of the radial bearing344. In the embodiment of FIGS. 7 and 8, a through hole 399 in themaintenance member 397 is configured to allow non-contact extension ofthe nose 377 of the magnet housing 340, thus allowing the magnet housing340, and thus magnet 338, to freely rotate. Ears 387, 389 are separatedby gaps 383, 385, and comprise a magnetically permeable material (e.g.,400 series stainless steel, iron, mu-metal, or another similar materialthat can attract a pole of the magnet 338). An edge 375 of each ear 387,389 may be flat, in order to allow a maximal amount of material to belocated in proximity to the magnet 338.

FIG. 18 illustrates an external adjustment device 1180 that is used tonon-invasively adjust the devices and systems described herein. Theexternal adjustment device 1180 comprises a magnetic hand piece 1178, acontrol box 1176 and a power supply 1174. The control box 1176 includesa control panel 1182 having one or more controls (buttons, switches ortactile, motion, audio or light sensors) and a display 1184. The display1184 may be visual, auditory, tactile, the like or some combination ofthe aforementioned features. The external adjustment device 180 maycontain software that allows programming by the physician.

FIG. 19 shows the detail of the magnetic hand piece 1178 of the externaladjustment device 1180. There is a plurality of, e.g., two (2), magnets1186 that have a cylindrical shape (also, other shapes are possible). Insome embodiments, the magnetic hand piece 1178 comprises only one magnet1186. In some embodiments, the magnetic hand piece 1178 uses one or moreelectromagnets. The magnets 1186 can be made from rare earth magnets(such as Neodymium-Iron-Boron), and can in some embodiments be radiallypoled. The magnets 1186 are bonded or otherwise secured within magneticcups 1187. The magnetic cups 1187 each include a shaft 1198, one ofwhich is attached to a first magnet gear 1212 and the other of which isattached to a second magnet gear 1214. The orientation of the poles ofeach the two magnets 1186 are maintained in relation to each other bymeans of the gearing system (by use of center gear 1210, that mesheswith both first magnet gear 1212 and second magnet gear 1214). In oneembodiment, the north pole of one of the magnets 1186 turnssynchronously with the south pole of the other magnet 1186, at matchingclock positions throughout a complete rotation. The configuration hasbeen known to provide an improved delivery of torque, for example tomagnet 338. Examples of methods and embodiments of external adjustmentdevices that may be used to adjust the intramedullary device 300, orother embodiments of the present invention, are described in U.S. Pat.No. 8,382,756, and U.S. patent application Ser. No. 13/172,598, both ofwhich are incorporated by reference herein.

The components of the magnetic hand piece 1178 are held together betweena magnet plate 1190 and a front plate 1192. Most of the components areprotected by a cover 1216. The magnets 1186 rotate within a staticmagnet cover 1188, so that the magnetic hand piece 1178 may be resteddirectly on the patient, while not imparting any motion to the externalsurfaces of the patient. Prior to distracting the intramedullarylengthening device 1110, the operator places the magnetic hand piece1178 over the patient near the location of the magnet 338. A magnetstandoff 1194 that is interposed between the two magnets 1186 contains aviewing window 1196, to aid in the placement. For instance, a mark madeon the patient's skin at the appropriate location with an indeliblemarker may be viewed through the viewing window 1196. To perform adistraction, the operator holds the magnetic hand piece 1178 by itshandles 1200 and depresses a distract switch 1228, causing motor 1202 todrive in a first direction. The motor 1202 has a gear box 1206 whichcauses the rotational speed of an output gear 1204 to be different fromthe rotational speed of the motor 1202 (for example, a slower speed).The output gear 1204 then turns a reduction gear 1208 which meshes withcenter gear 1210, causing it to turn at a different rotational speedthan the reduction gear 1208. The center gear 1210 meshes with both thefirst magnet gear 1212 and the second magnet gear 1214 turning them eachat the same rate. Depending on the portion of the body where the magnets1186 of the external adjustment device 1180 are located, it is desiredthat this rate be controlled, to minimize the resulting induced currentdensity imparted by magnet 1186 and magnet 338 through the tissues andfluids of the body. For example a magnet rotational speed of 60 RPM orless is contemplated although other speeds may be used such as 35 RPM orless. At any time, the distraction may be lessened by depressing theretract switch 1230, which can be desirable if the patient feelssignificant pain, or numbness in the area holding the device.

Throughout the embodiments presented, a magnet 338 is used as a drivingelement to remotely create movement in an intramedullary device 300.FIGS. 9-12 schematically show four alternate embodiments, wherein othertypes of energy transfer are used in place of permanent magnets.

FIG. 9 illustrates an intramedullary device 1300 comprising an implant1306 having a first implant portion 1302 and a second implant portion1304, the second implant portion 1304 being non-invasively displaceablewith respect to the first implant portion 1302. The first implantportion 1302 is secured to a first bone portion 197 and the secondimplant portion 1304 is secured to a second bone portion 199 within apatient 191. A motor 1308 is operable to cause the first implant portion1302 and the second implant portion 1304 to displace relative to oneanother. An external adjustment device 1310 has a control panel 1312 forinput by an operator, a display 1314 and a transmitter 1316. Thetransmitter 1316 sends a control signal 1318 through the skin 195 of thepatient 191 to an implanted receiver 1320. Implanted receiver 1320communicates with the motor 1308 via a conductor 1322. The motor 1308may be powered by an implantable battery, or may be powered or chargedby inductive coupling.

FIG. 10 illustrates an intramedullary device 1400 comprising an implant1406 having a first implant portion 1402 and a second implant portion1404, the second implant portion 1404 being non-invasively displaceablewith respect to the first implant portion 1402. The first implantportion 1402 is secured to a first bone portion 197 and the secondimplant portion 1404 is secured to a second bone portion 199 within apatient 191. An ultrasonic motor 1408 is operable to cause the firstimplant portion 1402 and the second implant portion 1404 to displacerelative to one another (e.g., a piezoelectric actuator). An externaladjustment device 1410 has a control panel 1412 for input by anoperator, a display 1414 and an ultrasonic transducer 1416 that iscoupled to the skin 195 of the patient 191. The ultrasonic transducer1416 produces ultrasonic waves 1418 which pass through the skin 195 ofthe patient 191 and operate the ultrasonic motor 1408.

FIG. 11 illustrates an intramedullary device 1700 comprising an implant1706 having a first implant portion 1702 and a second implant portion1704, the second implant portion 1704 being non-invasively displaceablewith respect to the first implant portion 1702. The first implantportion 1702 is secured to a first bone portion 197 and the secondimplant portion 1704 is secured to a second bone portion 199 within apatient 191. A shape memory actuator is operable to cause the firstimplant portion 1702 and the second implant portion 1704 to displacerelative to one another. An external adjustment device 1710 has acontrol panel 1712 for input by an operator, a display 1714 and atransmitter 1716. The transmitter 1716 sends a control signal 1718through the skin 195 of the patient 191 to an implanted receiver 1720.Implanted receiver 1720 communicates with the shape memory actuator 1708via a conductor 1722. The shape memory actuator 1708 may be powered byan implantable battery, or may be powered or charged by inductivecoupling.

FIG. 12 illustrates an intramedullary device 1800 comprising an implant1806 having a first implant portion 1802 and a second implant portion1804, the second implant portion 1804 being non-invasively displaceablewith respect to the first implant portion 1802. The first implantportion 1802 is secured to a first bone portion 197 and the secondimplant portion 1804 is secured to a second bone portion 199 within apatient 191. A hydraulic pump 1808 is operable to cause the firstimplant portion 1802 and the second implant portion 1804 to displacerelative to one another. An external adjustment device 1810 has acontrol panel 1812 for input by an operator, a display 1814 and atransmitter 1816. The transmitter 1816 sends a control signal 1818through the skin 195 of the patient 191 to an implanted receiver 1820.Implanted receiver 1820 communicates with the hydraulic pump 1808 via aconductor 1822. The hydraulic pump 1808 may be powered by an implantablebattery, or may be powered or charged by inductive coupling. Thehydraulic pump 1808 may alternatively be replaced by a pneumatic pump.

FIG. 13 illustrates a bone 100 which is incomplete and missing aportion. The bone 100 includes a proximal portion 102 and a distalportion 104. The bone 100 has a proximal end 106 and a distal end 108,and a medullary canal 110 extending between the two. The bone mayrepresent a number of different long bones, for example, a femur, atibia, a fibula, a humerus, or others, or even other bones (e.g., amandible). An open area 112 between the proximal portion 102 and thedistal portion 104 represents the missing bone. The open area 112 mayexist for any of a number of reasons. For example, that portion of thebone 100 may have been lost during a traumatic accident or during one ormore surgical procedures after a traumatic accident. Or, it may havebeen removed along with the resection of a portion of cancerous bone,for example, a tumor caused by one or more types of sarcoma.

In FIG. 14, a system for bone transport 400 is shown attached to thebone 100. The system for bone transport comprises an adjustable-lengthimplant 401 and a support member 403. The adjustable-length implant 401may in some embodiments comprise an intramedullary limb lengtheningdevice, such as the intramedullary device 300 of FIGS. 1-8 or anyembodiments shown in FIGS. 9-12. The adjustable implant 401 comprises arod 402 which is telescopically displaceable from a housing 404. The rod402 may be distracted out of or retracted into the housing 404 by adriving element 405. In use, the adjustable-length implant 401 may beimplanted within the medullary canal 110 of the bone 100 after themedullary canal 110 has been drilled or reamed to remove material or toincrease its inner diameter. Prior to or following the implantation ofthe adjustable-length implant 401, an osteotomy 406 can be made, bycutting, sawing, etc., to create a transport portion 114 of the bone100. In FIG. 14, the transport portion 114 is created from the distalportion 104 of the bone 100. In other cases, the transport portion 114may be made from the proximal portion 102 of the bone 100. In FIG. 14,the adjustable-length implant 401 is inserted from the proximal end 106of the bone 100 (i.e., in an antegrade manner). But, in other cases, theadjustable-length implant 401 may be inserted from the distal end 108(i.e., in a retrograde manner). With the transport portion 114 separatedfrom the distal portion 104 of the bone 100 by the osteotomy 406. Thetransport portion 114 and the proximal portion 102 may be coupled to theadjustable-length implant 401 in order to move the transport portion 114with respect to the proximal portion 102 and distal portion 104. Toattach the pieces of the bone 100, the proximal portion 102 of the bone100 may be drilled on an axis through one or more holes 410 in thehousing 404 and one or more bone screws 408 are placed through the oneor more holes 410 and secured to the proximal portion 102 of the bone100. The transport portion 114 of the bone 100 may be drilled on an axisthrough one or more holes 412 in the rod 402 and one or more bone screws414 can be placed through the one or more holes 412 and secured to thetransport portion 114 of the bone 100. The transport portion 114 maythen be non-invasively moved along a longitudinal axis Z of theadjustable-length implant 401. The adjustable-length implant 401 asdepicted in FIG. 14 may be supplied to the user in a fully or mostlyextended condition (with the rod 402 fully or substantially distractedfrom the housing 404), so that the transport process moves the transportportion 114 away from the distal portion 104 and towards the proximalportion 102. In this traction manner, the transport portion 114 ispulled not pushed. Pulling on the transport portion 114 tends to provideincreased dimensional stability and less drift as the transport portion114 is being moved. Once a callus begins to acceptably form at theosteotomy 406, the transport process may be started. For example, thetransport portion 114 may be moved between about 0.5 mm per day andabout 1.50 mm per day, or between about 0.75 mm per day and about 1.25mm per day, or around 1.00 mm per day. Each daily distraction amount maybe achieved in one non-invasive adjustment per day, or may be broken upinto two, three, or more separate adjustments (for example, threeadjustments of about 0.33 mm each). Due to the osteogenesis that canoccur during controlled transport of the transport portion 114, a newbone portion 416 is created. When the bone transport proceeds to theextent such that a proximal end 418 of the transport portion 114 reachesa distal end 420 of the proximal portion 102, a compressive force may beapplied to the transport portion 114 and the proximal portion 102. Suchcompressive forces can help fuse or adhere the transport portion 114 tothe proximal portion, and is aided by the fact that it is being appliedby pulling the transport portion 114.

As mentioned above, the system for bone transport 400 may also include asupport member 403, which may comprise a bone plate configured to besecured to a location on an external surface 422 of the bone 100. Thebone plate may comprise a cortical bone plate. The support member 403may include one or more holes 424 at its distal end 426 for placement ofone or more bone screws 428. The support member 403 may also include oneor more holes 430 at its proximal end 432 for placement of one or morebone screws 434, 436. The bone screws 434, 428 may be bicortical bonescrews and the bone screw 436 may be a unicortical bone screw.Bicortical bone screws may advantageously be used at locations on thebone 100 that are proximal or distal to the adjustable-length implant401, while unicortical bone screws may advantageously be used atlocations on the bone 100 that are adjacent the adjustable-lengthimplant 401. The bone screws 428, 434, 436 that are used to secure thesupport member 403 to the bone 100 may have threaded shafts and tapered,threaded heads that are configured such that the threaded shafts engagewith bone material and the tapered threaded heads engage with taperedthreaded holes (e.g., the one or more holes 424, 430) in the supportmember 403. The support member 403 maintains the proximal portion 102and the distal portion 104 of the bone 100 static and stable withrespect to each other, thereby optimizing the precision of movement ofthe transport portion 114 as it is moved in relation to the proximalportion 102 and the distal portion 104. One or more cerclages 429, 431may be used to further secure the system in place, for example, tofurther secure the support member 403 to the bone 100. While thecerclages 429, 431 are omitted in FIG. 15, it should be understood thatthey may be used with any embodiment of apparatus or methods describedherein. In some embodiments, the support member 403 may includeconsiderably more holes for placement of bone screws. For example, aportion of the support member 403 configured to be placed at theproximal end of a femur may have three, four, or more holes forplacement of bone screws which are configured to be secured into boneand extend into the femoral neck, the greater trochanter, or otherportions of the femur, including one or more bone fragments.

FIGS. 16 and 17 illustrate the system for bone transport 400 secured tothe bone 100. The adjustable-length implant 401, however, has beeninserted into the medullary canal 110 from the distal end 108 of thebone (i.e., in a retrograde manner). The osteotomy 406 is thus made inthe proximal portion 102 of the bone 100, and the transport portion 114is detached from the proximal portion 102 of the bone. The transportportion 114 is transported away from the proximal portion 102 of thebone 100 and towards the distal portion 104 of the bone 100, to createthe new bone portion 416.

An alternative anatomical setup may be created during surgery, byplacing the adjustable-length implant 401 in an orientation similar tothat of FIG. 14 (e.g., rod 402 extending distally or oriented downwardand housing 404 extending proximally or oriented upward), but byinserting it retrograde (i.e., from the distal end 108 of the bone 100)as shown in FIG. 16. Still another alternative anatomical setup may becreated in surgery, by placing the adjustable-length implant 401 in anorientation similar to that of FIG. 16 (e.g., rod 402 extendingproximally or oriented upward and housing 404 extending distally ororiented downward), but by inserting it antegrade (i.e., from theproximal end 106 of the bone 100) as shown in FIG. 14.

FIG. 20 illustrates a system for bone transport 500. The system for bonetransport comprises an adjustable-length implant 501 and a supportmember 503 (for example, a plate). The adjustable-length implant 501 mayin some embodiments comprise an intramedullary limb lengthening device,such as the intramedullary device 300 of FIGS. 1-8 or any of thealternative embodiments of FIGS. 9-12. The adjustable implant 501 maycomprise a rod 502, which is telescopically displaceable from a housing504. The rod 502 may be distracted out of or retracted into the housing504 by a driving element 505 (shown in FIGS. 21-22). In use, theadjustable-length implant 501 is implanted within the medullary canal110 of the bone 100, after the medullary canal 110 has been drilled orreamed, to remove material or to increase its inner diameter. Prior toor following this, an osteotomy 406 is made, by cutting, sawing, etc.,to create a transport portion 114 of the bone 10. In FIG. 21, thetransport portion 114 is created from the distal portion 104 of the bone100. In other cases, the transport portion 114 may be made from theproximal portion 102 of the bone 100. FIG. 21 illustrates theadjustable-length implant 501 after having been inserted in an antegrademanner. But in other cases the adjustable-length implant 501 may beinserted in a retrograde manner. After separation of the transportportion 114 from the distal portion 104 of the bone 100 (e.g., by theosteotomy 406), the transport portion 114 and the proximal portion 102may be coupled to the adjustable-length implant 501 in order to move thetransport portion 114 with respect to the proximal portion 102 anddistal portion 104. The proximal portion 102 of the bone 100 may bedrilled on an axis through one or more holes 510 in the housing 504 andone or more bone screws 508 may be placed through the one or more holes510 and secured to the proximal portion 102 of the bone 100. Thetransport portion 114 of the bone 100 may be drilled on an axis throughone or more holes 512 in the rod 502 and one or more bone screws 514 maybe placed through the one or more holes 512 and secured to the transportportion 114 of the bone 100. The transport portion 114 may then benon-invasively moved along a longitudinal axis Z of theadjustable-length implant 501. The adjustable-length implant 501 asdepicted in FIG. 21 may be supplied to the user in a fully or mostlyextended condition (with the rod 502 fully or substantially distractedfrom the housing 504), so that the transport process moves the transportportion 114 away from the distal portion 104 and towards the proximalportion 102 In this traction manner, the transport portion 114 is pullednot pushed. Pulling on the transport portion 114 tends to provideincreased dimensional stability and less drift as the transport portion114 is being moved. The support member 503 is similar to the supportmember 403 of FIGS. 14-17, except that the support member 503 comprisesa longitudinal slot 587 extending between a proximal slot end 589 and adistal slot end 597. The slot 587 is located between the proximal end532 and the distal end 526 of the support member 503. As in theembodiments shown in FIGS. 14-17, the support member 502 may be securedto the bone 100 with one or more bicortical bone screws 528, 534 (whichcan be placed through holes 524, 530) and one or more unicortical bonescrews 536 (which are placed through holes 524, 530). As shown in FIG.20, certain holes 524 a. 524 c may be offset to one side of centerline599 of the support member 503, while other holes 524 b, may be offset toanother side of centerline 599 of the support member 503. Offsetting theholes in this fashion may aid the placement of bicortical bone screws,in cases wherein the adjustable-length implant 501 extends to the levelof the holes 524 a-c. The offset location of the holes 524 a-c, forexample, may allow the bicortical bone screws to extend past the rod 502on either side of the rod 502. The transport portion 114 of the bone 100can be secured to the rod 502 by the bone screws 514 by drilling thebone 100 in the transport portion along the axes of the holes 512 in amanner such that when the bone screws 514 are secured, they extend froman external location 593 of the slot 587 of the support member 503,through the slot 587, and into the bone 100 of the transport portion114. The bone screws 514 are aligned in a manner such that when the rod502 is non-invasively translated with respect to the housing 504, theshaft 597 of the bone screws 514 slide within the slot 587. As will bereadily appreciated, the diameter of the shaft 597 of the bone screw 514is less than the width of the slot 587. In some embodiments, thediameter of the head 595 of the bone screw 514 is greater than the widthof the slot 587, thereby further stabilizing the transport portion 114and limiting its ability to displace in along an x-axis. Turning to FIG.22, the transport portion 114 itself is limited by the support member503 so that the transport portion 114 does not translate (drift)substantially in the positive x direction. The transport portion 114 mayalso be limited by the head 595 of the bone screw 514 so that thetransport portion 114 does not translate substantially in the negative xdirection, either during longitudinal adjustment of the transportportion, or when at rest.

In bone transport or limb lengthening, the transport or distractionlengths can vary greatly from procedure to procedure and/or patient topatient. In bone transport procedures, the transport length may be afunction of the length of bone that is missing and the length of thetransport portion 114 created during surgery. An adjustable-lengthimplant kit 600 (shown in in FIG. 23) may be configured to allow theuser to create an adjustable-length implant, for example theadjustable-length implant 601 of FIG. 24, tailored to the particulartransport length or distraction length of the patient to be treated. Theadjustable-length implant kit 600 may include a base actuator 605comprising a housing 604, a base rod 602, and one or more rod extensions(e.g., rod extensions 606, 608, 610). The base rod 602 may betelescopically moveable within the housing 604 (as described elsewhereherein) and has an internally threaded portion 612. Each of the rodextensions 606, 608, 610 has an externally threaded portion 614 which isconfigured to be screwed into the internally threaded portion 612 of thebase rod 602. A user (e.g., surgeon or physician) may choose theappropriate rod extension 606, 608, 610 for the particular patient. Forexample, rod extension 606 may be chosen if a relatively long transportor distraction length is required, whereas rod extension 610 may bechosen if a relatively short transport or distraction length isrequired. It will be understood that the rod extensions 606, 608, 610may have varying properties, including but not limited to: numbers ofanchor holes 616; axial orientation of anchor holes 616; anchor holediameters (e.g., for use with bone screw of different diameters); etc.The rod extensions 606, 608, 610 may include a hollow portion. Forexample, an interior passage 618 may pass through the end of the rodextension 610 (or any other rod extension 606, 608) which has theexternally threaded portion 614. In that way, the lead screw (not shown)may extend into the interior passage 618, e.g., if the lead screwextends from the interior of the base rod 602. In some embodiments, thelead screw may be extendible (i.e., may have an end that may beaugmented by an extension portion of lead screw). The internallythreaded portion 612 and the externally threaded portion 614 may eachhave a locking feature, incorporating, for example, a latch, snap,detent, hook, or friction fit feature that secures the rod extension606, 608, 610 and the base rod 602 when the rod extension 606, 608, 610to the base rod 602 are coupled (e.g., screwed together). In analternative embodiment, the base rod 602 may include an externallythreaded portion and the rod extensions 606, 608, 610 may each includean internally threaded portion. The adjustable-length implant kit 600 ofFIGS. 23-24 may be used in standard limb lengthening procedures, or inbone transport procedures, including, but not limited to, thosedescribed herein. By having the adjustable-length implant kit 600available during surgery, a surgeon or physician may more easily selectand/or construct a device most appropriate for the patient beingtreated. In some embodiments, the rod extensions 606, 608, 610 may beeasily sterilized (e.g., steam sterilization/autoclave, gas) which maylower the cost of the procedure, especially if the base actuator 605must be supplied sterile by the supplier. In use, a surgeon or physician(which should be understood to include any other medical professional,such as those under the control or direction of a surgeon or physician)may attach one rod extension, and remove it and replace it with another,if it does not fit the patient properly. In alternative embodiments andmethods, the support member 403, 503 may be replaced by an externalfixator comprising a base which is configured to be located external tothe patient, a first pin configured to attach at one end to the base andat another end to be coupled to the first portion of the bone, and asecond pin configured to attach at one end to the base and at anotherend be coupled to the second portion of the bone.

Although this invention has been disclosed in the context of certainpreferred embodiments and examples, it will be understood by thoseskilled in the art that the present invention extends beyond thespecifically disclosed embodiments to other alternative embodimentsand/or uses of the invention and obvious modifications and equivalentsthereof. In addition, while a number of variations of the invention havebeen shown and described in detail, other modifications, which arewithin the scope of this invention, will be readily apparent to those ofskill in the art based upon this disclosure. It is also contemplatedthat various combinations or sub-combinations of the specific featuresand aspects of the embodiments may be made and still fall within thescope of the invention. Accordingly, it should be understood thatvarious features and aspects of the disclosed embodiments can becombined with or substituted for one another in order to form varyingmodes of the disclosed invention. Thus, it is intended that the scope ofthe present invention herein disclosed should not be limited by theparticular disclosed embodiments described above, but should bedetermined only by a fair reading of the claims that follow.

Similarly, this method of disclosure, is not to be interpreted asreflecting an intention that any claim require more features than areexpressly recited in that claim. Rather, as the following claimsreflect, inventive aspects lie in a combination of fewer than allfeatures of any single foregoing disclosed embodiment. Thus, the claimsfollowing the Detailed Description are hereby expressly incorporatedinto this Detailed Description, with each claim standing on its own as aseparate embodiment.

What is claimed is:
 1. A system for bone transport comprising: an adjustable length implant configured to intramedullary placement, the adjustable length implant including a housing configured to be coupled to a first bone portion and a rod configured to be coupled to a transport bone portion, wherein the rod is moveable relative to the housing; and a support member having a first end configured to be coupled to the first bone portion and a second end configured to be coupled to a second bone portion, wherein the rod is configured to move the transport bone portion relative to the first bone portion and the second bone portion.
 2. The system of claim 1, wherein the support member is configured to maintain a position of the first bone portion relative to the second bone portion while the rod moves the transport bone portion relative to the first bone portion and the second bone portion.
 3. The system of claim 1, wherein the support member includes a longitudinally extending slot disposed between the first end and the second end of the support member.
 4. The system of claim 3, further comprising: an elongate anchor member configured to extend through the longitudinally extending slot to be coupled with the rod and the transport bone portion.
 5. The system of claim 4, wherein the elongate anchor is slidable within the longitudinally extending slot of the support member as the transport bone portion moves relative to the first bone portion and the second bone portion.
 6. The system of claim 1, further comprising: a driving element configured to be non-invasively actuated to displace the rod relative to the housing.
 7. The system of claim 6, wherein the driving element comprises a permanent magnet.
 8. The system of claim 7, wherein the permanent magnet comprises a radially poled rare earth magnet.
 9. The system of claim 6, wherein the driving element comprises a motor.
 10. The system of claim 6, wherein the driving element comprises an inductively coupled motor.
 11. The system of claim 6, wherein the driving element comprises an ultrasonically actuated motor.
 12. The system of claim 6, wherein the driving element comprises a piezoelectric element.
 13. The system of claim 6, wherein the driving element comprises a subcutaneous hydraulic pump.
 14. The system of claim 6, wherein the driving element comprises a shape-memory driven actuator.
 15. The system of claim 1, wherein the support member comprises one or more holes at one or more of its distal end and proximal end, the one or more holes each configured to pass a bone screw.
 16. The system of claim 15, wherein the one or more holes each have a female thread, configured to engage a male thread carried by a head of a bone screw.
 17. The system of claim 1, wherein the adjustable-length implant is configured such that when the driving element is non-invasively activated, the distance between the first end and the second end of the adjustable-length implant can be controllably shortened.
 18. The system of claim 1, further comprising: an external adjustment device configured to cause displacement of the rod relative to the housing.
 19. A system for bone transport comprising: an adjustable length implant configured to intramedullary placement, the adjustable length implant including a housing configured to be coupled to a first bone portion and a rod configured to be coupled to a transport bone portion, wherein the rod is moveable relative to the housing; and a support member having a first end configured to be coupled to the first bone portion and a second end configured to be coupled to a second bone portion; and an external adjustment device configured to cause displacement of the rod relative to the housing, wherein the rod is configured to move the transport bone portion relative to the first bone portion and the second bone portion upon, and wherein the support member is configured to maintain a position of the first bone portion relative to the second bone portion. 